The present invention relates generally to methods and systems for qualifying and calibrating beam delivery systems. More specifically, embodiments of the present invention relate to methods and systems for qualifying and calibrating a opthalmological surgery laser beam delivery system based on a laser beam delivery system characteristic.
Laser based systems are commonly used in opthalmological surgery on corneal tissues of the eye to correct vision defects. These systems use lasers to achieve a desired change in corneal shape, with the laser removing microscopic layers of stromal tissue from the cornea using a technique generally described as ablative photodecomposition to alter the refractive characteristics of the eye. Laser eye surgery techniques are useful in procedures such as photorefractive keratotomy (PRK), phototherapeutic keratectomy (PTK), laser in situ keratomileusis (LASIK), and the like.
Laser ablation procedures can reshape or sculpt the shape of the cornea for varying purposes, such as for correcting myopia, hyperopia, astigmatism, and other corneal surface profile defects. In known systems, the laser beam often comprises a series of discrete pulses of laser light energy, with the total shape and amount of tissue being removed being determined by the position, shape, size, and/or number of a pattern of laser energy pulses impinging on the cornea. A variety of algorithms may be used to calculate the pattern of laser pulses used to reshape the cornea so as to correct a refractive error of the eye.
Accurate control of the laser beam delivery system is crucial for patient safety and successful vision correction. Accordingly, laser beam delivery systems are qualified and calibrated to ensure control over the positioning and distribution of ablation energy across the cornea so as to minimize undesirable laser system performance, which may result from flawed internal mechanical or optical components, misalignment, and the like. In particular, qualification and calibration of the laser system helps ensure accurate removal of the intended shape and quantity of the corneal tissue so as to provide the desired shape and refractive power modification to the patient's cornea. Imprecise control of the laser beam may jeopardize the success of the surgery and could cause damage to the patient's eye. For example, deviation from a desired laser beam path or position may result in tissue ablation at an undesired location on the patient's cornea which in turn leads to less than ideal corneal sculpting results. As such, it is beneficial to provide precise control over the positioning of the laser beam so as to accurately sculpt the patient's cornea through laser ablation.
In light of the above, it would be desirable to provide improved methods and systems for qualifying and calibrating beam delivery systems on the basis of beam path positioning and other related beam path and beam delivery system characteristics. It would be further desirable if such methods and systems enhanced qualification and calibration accuracy without significantly increasing the overall system cost and complexity. At least some of these objectives will be met by the methods and systems described herein.